Burkhard Bilger has a fascinating article in the New Yorker about modern strongman competitions. He addresses their history, their competitors and what they physically demand from athletes. One particularly interesting topic is why many champions in the sport don't look extraordinarily strong:

And I remember, as a boy, being a little puzzled by the fact that the best weight lifter in the world—Vasily Alexeyev, a Russian, who broke eighty world records and won gold medals at the Munich and the Montreal Olympics—looked like the neighborhood plumber. Shaggy shoulders, flaccid arms, pendulous gut: what made him so strong?

“Power is strength divided by time,” John Ivy, a physiologist at the University of Texas, told me. “The person that can generate the force the fastest will be the most powerful.” This depends in part on what you were born with: the best weight lifters have muscles with far more fast-twitch fibres, which provide explosive strength, than slow-twitch fibres, which provide endurance. How and where those muscles are attached also matters: the longer the lever, the stronger the limb. But the biggest variable is what’s known as “recruitment”: how many fibres can you activate at once? A muscle is like a slave galley, with countless rowers pulling separately toward the same goal. Synchronizing that effort requires years of training and the right “neural hookup,” Ivy said. Those who master it can lift far above their weight. Max Sick, a great early-nineteenth-century German strongman, had such complete muscle control that he could make the various groups twitch in time to music. He was only five feet four and a hundred and forty-five pounds, yet he could take a man forty pounds heavier, press him in the air sixteen times with one hand, and hold a mug of beer in the other without spilling it.